Bootloader source code

Untar the sources, apply the patch. run "make gta01bv3_config" (or gta01bv2_config, or whatever hardware revision you have), run "make". You will get a resulting "u-boot.bin" image, which you can directly flash (either using existing bootloader or sjf2410-linux) into NAND.

Bootloader development

QT2410

If you want to do bootloader development on the QT2410, it's easier to work with a bootloader image that can be downloaded via USB into RAM instead of flashing.

To do so, you need to edit the u-boot/include/configs/qt2410.h file, and change the "if 0" in Line 32 into a "if 1", then recompile with "make".

The resulting "u-boot.bin" is _NOT SUITABLE_ for NAND flash, but only for direct execution from within ram, e.g. by using the s3c2410_boot_usb program.

GTA01

Doing bootloader development on the GTA01 is a bit more tricky. first, we don't have any NOR flash. Second, there is no other way to boot _but_ from NAND. Therefore, we also don't have a USB downloader like the QT2410.

The main problem is: The S3C2410 Steppingstone unconditionally copies the first 4k of flash into its internal SRAM. That SRAM segment stays unconditionally mapped at physical address zero. How do we get around this

Boot menu

As of the Phase-0 release, our u-boot version now features an on-screen boot menu.

Accessing the boot menu

You can access the boot meny by pressing and holding the Neo1973 AUX button together with the power button while switching the phone on.

Using the boot menu

By pressing the Neo1973 AUX button you can cycle through the menu items. Use the POWER button to select one item.

Adding items to the boot menu

You can add items to the boot menu by setting environment variables. FIXME.

Bootloader prompt

Accessing the bootloader prompt

The bootloader prompt is available either on the serial console (via Debug Board), or as virtual USB Serial device (USB CDC_ACM).
Whether the serial port or usb i used depends on the u-boot environment variables stdin, stdout and stderr.

Whether or not you use usbtty, the first couple of messages will always be displayed on the serial console.

The bootloader is currently configured to waid for three seconds. If a key press on the stdin is received within those three seconds, auto-boot is aborted.

Using usbtty from Linux

Just by connecting the phone in u-boot mode to your Linux pc should make it detect a CDC ACM device, and you should get a new tty device called /dev/ttyACM0. Use your favourite terminal emulator (minicom, cu, zc, screen ...) to access it like any other serial port. If you don't have a favorite, try just "cu -l /dev/ttyACM0".

First, you should try to check whether the USB device shows up in 'lsusb' while you're running in u-boot mode:

Disabling battery charging

Forcing fast charge

you can force the PMU to try to do a fast (500mA) charge of the battery. It will abort if the battery is in over temperature or some other error condition occurs.

Enabling / Disabling automatic fast charge

Autofast is a feature of the PCF50606 PMU. It means that the fast_cccv mode will be automatically selected if a charger with suitable voltage is plugged in, and the battery not in over temperature condition.

WARNING: This is potentially dangerous. Only enable autofast if you ARE SURE that you can draw 500mA from the USB connector. This is the case with a wall outlet charger, or if you are attached to a self-powered hub or a desktop PC root hub. Bus powered hubs and some laptops only provide 100mA on their USB ports and can thus not support fast charging

Bootloader source code

Untar the sources, apply the patch. run "make gta01bv3_config" (or gta01bv2_config, or whatever hardware revision you have), run "make". You will get a resulting "u-boot.bin" image, which you can directly flash (either using existing bootloader or sjf2410-linux) into NAND.

Bootloader development

QT2410

If you want to do bootloader development on the QT2410, it's easier to work with a bootloader image that can be downloaded via USB into RAM instead of flashing.

To do so, you need to edit the u-boot/include/configs/qt2410.h file, and change the "if 0" in Line 32 into a "if 1", then recompile with "make".

The resulting "u-boot.bin" is _NOT SUITABLE_ for NAND flash, but only for direct execution from within ram, e.g. by using the s3c2410_boot_usb program.

GTA01

Doing bootloader development on the GTA01 is a bit more tricky. first, we don't have any NOR flash. Second, there is no other way to boot _but_ from NAND. Therefore, we also don't have a USB downloader like the QT2410.

The main problem is: The S3C2410 Steppingstone unconditionally copies the first 4k of flash into its internal SRAM. That SRAM segment stays unconditionally mapped at physical address zero. How do we get around this

Boot menu

As of the Phase-0 release, our u-boot version now features an on-screen boot menu.

Accessing the boot menu

You can access the boot meny by pressing and holding the Neo1973 AUX button together with the power button while switching the phone on.

Using the boot menu

By pressing the Neo1973 AUX button you can cycle through the menu items. Use the POWER button to select one item.

Adding items to the boot menu

You can add items to the boot menu by setting environment variables. FIXME.

Bootloader prompt

Accessing the bootloader prompt

The bootloader prompt is available either on the serial console (via Debug Board), or as virtual USB Serial device (USB CDC_ACM).
Whether the serial port or usb i used depends on the u-boot environment variables stdin, stdout and stderr.

Whether or not you use usbtty, the first couple of messages will always be displayed on the serial console.

The bootloader is currently configured to waid for three seconds. If a key press on the stdin is received within those three seconds, auto-boot is aborted.

Using usbtty from Linux

Just by connecting the phone in u-boot mode to your Linux pc should make it detect a CDC ACM device, and you should get a new tty device called /dev/ttyACM0. Use your favourite terminal emulator (minicom, cu, zc, screen ...) to access it like any other serial port. If you don't have a favorite, try just "cu -l /dev/ttyACM0".

First, you should try to check whether the USB device shows up in 'lsusb' while you're running in u-boot mode:

Disabling battery charging

Forcing fast charge

you can force the PMU to try to do a fast (500mA) charge of the battery. It will abort if the battery is in over temperature or some other error condition occurs.

Enabling / Disabling automatic fast charge

Autofast is a feature of the PCF50606 PMU. It means that the fast_cccv mode will be automatically selected if a charger with suitable voltage is plugged in, and the battery not in over temperature condition.

WARNING: This is potentially dangerous. Only enable autofast if you ARE SURE that you can draw 500mA from the USB connector. This is the case with a wall outlet charger, or if you are attached to a self-powered hub or a desktop PC root hub. Bus powered hubs and some laptops only provide 100mA on their USB ports and can thus not support fast charging